//
// ========================================================================
// Copyright (c) 1995-2015 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
//
package com.ejtone.mars.kernel.util.lifecycle;

import java.util.EventListener;

public interface LifeCycle {
	/**
	 * Starts the component.
	 * 
	 * @throws Exception If the component fails to start
	 * @see #isStarted()
	 * @see #stop()
	 * @see #isFailed()
	 */
	public void start( ) throws Exception;

	/**
	 * Stops the component.
	 * The component may wait for current activities to complete
	 * normally, but it can be interrupted.
	 * 
	 * @exception Exception If the component fails to stop
	 * @see #isStopped()
	 * @see #start()
	 * @see #isFailed()
	 */
	public void stop( ) throws Exception;

	/**
	 * @return true if the component is starting or has been started.
	 */
	public boolean isRunning( );

	/**
	 * @return true if the component has been started.
	 * @see #start()
	 * @see #isStarting()
	 */
	public boolean isStarted( );

	/**
	 * @return true if the component is starting.
	 * @see #isStarted()
	 */
	public boolean isStarting( );

	/**
	 * @return true if the component is stopping.
	 * @see #isStopped()
	 */
	public boolean isStopping( );

	/**
	 * @return true if the component has been stopped.
	 * @see #stop()
	 * @see #isStopping()
	 */
	public boolean isStopped( );

	/**
	 * @return true if the component has failed to start or has failed to stop.
	 */
	public boolean isFailed( );

	public void addLifeCycleListener( LifeCycle.Listener listener );

	public void removeLifeCycleListener( LifeCycle.Listener listener );

	/**
	 * Listener.
	 * A listener for Lifecycle events.
	 */
	public interface Listener extends EventListener {
		public void lifeCycleStarting( LifeCycle event );

		public void lifeCycleStarted( LifeCycle event );

		public void lifeCycleFailure( LifeCycle event, Throwable cause );

		public void lifeCycleStopping( LifeCycle event );

		public void lifeCycleStopped( LifeCycle event );
	}

}
